Isolate nested sample screens from main game to avoid toolbar interactions

osu.Game/Overlays/FirstRunSetup/ScreenUIScale.cs

@@ -126,6 +126,7 @@ namespace osu.Game.Overlays.FirstRunSetup
         private class SampleScreenContainer : CompositeDrawable
         {
             private readonly OsuScreen screen;
+
             // Minimal isolation from main game.
 
             [Cached]
@@ -151,6 +152,9 @@ namespace osu.Game.Overlays.FirstRunSetup
                 RelativeSizeAxes = Axes.Both;
             }
 
+            protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) =>
+                new DependencyContainer(new DependencyIsolationContainer(base.CreateChildDependencies(parent)));
+
             [BackgroundDependencyLoader]
             private void load(AudioManager audio, TextureStore textures, RulesetStore rulesets)
             {
@@ -197,5 +201,41 @@ namespace osu.Game.Overlays.FirstRunSetup
                 stack.PushSynchronously(screen);
             }
         }
+
+        private class DependencyIsolationContainer : IReadOnlyDependencyContainer
+        {
+            private readonly IReadOnlyDependencyContainer parentDependencies;
+
+            private readonly Type[] isolatedTypes =
+            {
+                typeof(OsuGame)
+            };
+
+            public DependencyIsolationContainer(IReadOnlyDependencyContainer parentDependencies)
+            {
+                this.parentDependencies = parentDependencies;
+            }
+
+            public object Get(Type type)
+            {
+                if (isolatedTypes.Contains(type))
+                    return null;
+
+                return parentDependencies.Get(type);
+            }
+
+            public object Get(Type type, CacheInfo info)
+            {
+                if (isolatedTypes.Contains(type))
+                    return null;
+
+                return parentDependencies.Get(type, info);
+            }
+
+            public void Inject<T>(T instance) where T : class
+            {
+                parentDependencies.Inject(instance);
+            }
+        }
     }
 }